class_docstr: Abstract agent class.
code: def eval_mode(self):
      orig_mode = self.training
      try:
          self.training = False
          yield
      finally:
          self.training = orig_mode
  
imports: import contextlib
  import os
  from abc import ABCMeta, abstractmethod, abstractproperty
  from typing import Any, List, Optional, Sequence, Tuple
  import torch
label_desc: Use image node_id 6 for calling the Agent obj's underlying member method code with example usage: obj.eval_mode() without return types